Vertical vibration analysis of soil-pile interaction systems considering the soil-pile interface behavior

A numerical method is presented herein to study soil-pile interaction systems in a stratified media. The method is based on a coupling of the finite element method and the boundary element method. The near field is modeled by the finite elements whereas the far field is modeled by the boundary element formulation using the multi-layer dynamic fundamental solution that satisfies the radiation condition of the waves. The two fields are coupled by imposing the displacement compatibility conditions at the interface between the near and far fields. Special attention is paid to the soil-pile interface using elastic springs to model the discontinuity at the interface. In order to validate the analytical approach, a forced vibration test is simulated and the response under vertical harmonic loads at the pile cap in the layered half plane is calculated. The results are compared with the published theoretical and experimental results. Finally, numerical analyses of various soil-pile systems are performed to examine the dynamic behavior of the system depending on parameters such as the elastic modulus of the pile and the stiffness of the interface springs.